25 July 2007

Observing Location	TotL
Observational Period	2045-2315 EDT
Atmospheric Conditions	Cloud Cover Scattered Clouds becoming Overcast Temperature 72°F Wind Calm Humidity 83%-87% Feels Like A little cool and moist When I arrived it was mostly clear and the temperature was moderate. Clouds filled in and it became mostly overcast and the humidity increased, which made it feel a little cool. When I left everything that I had laying on the ground felt moist including the coffee can covers that were zipped up inside the insulated lunch box. Transparency Poor Seeing II
Instruments	SAR: Coulter CT-100 Newtonian reflector - Charlie ~24mm Kellner w/helical focuser (18x) Celestron Omni 20mm (21x) Celestron Omni 2x Barlow
Observing Party	Charlie Ridgway Kin Lee

Target Jupiter Constellation Oph Category Planet Time yyyymmdd.hhmm 20070725.2045 EDT Comments Object Class Classical Planet Elongation ° Distance Light Time (from Earth) AU ms Distance (from Sun) Au Angular Size 42.5" Magnitude -2.4 Central Meridian I/II 72.48°/202.88° Altitude 27° Moons Starry Night Starter graphic The Moon, Jupiter and Antares are forming a large triangle on the left side of the scorpion. Starry Night Starter graphic Jupiter’s moons are fairly evenly spaced, two on each side of the planet.

Target C/2006 VZ13 (LINEAR) Constellation Com Category Comet Time yyyymmdd.hhmm 20070725.2145 EDT Comments Kin arrived with his Palm so we tried hopping to the comet when gaps in the clouds passed over the area. What should have been a cakewalk turned out to be an impossibility. The hop to the location of the comet is easy and I wasn’t having any trouble following it in the scope or confirming my location, but the continual passage of clouds made it hard to keep moving. Kin had to leave before I got there. I looked at his Palm before he left to get an idea of the star field but I didn’t think to get the comet’s RA and Dec from him so I could find it in my S&T Pocket Star Atlas. I finally gave up on at about 2215 EST when I big cloud came in and I wanted to get ready for the main event of the evening. Carted du Ciel graphic

Target Moon Constellation Sco Category Lunar Time yyyymmdd.hhmm 20070725.2215 EDT Comments Lunation 1046 Phase Waxing Gibbous Age 11.59d Distance Light Time (from earth) 394,369 km s Elongation ° % Illuminated 83.8% Morning Terminator Colongitude (λ E) 46.6° Evening Terminator Colongitude (λ W) 226.6° Libration in Latitude +7.32° Libration in Longitude -4.08° Magnitude -12.45 Angular Size 30'30" Altitude 20°49’ Virtual Moon Atlas graphic The main reason for coming out under what were predicted to have been marginal conditions was to try to see the Lacross 4 satellite pass over the disc of the Moon which was supposed to have happened at 2248 EST. I didn’t see it. The satellite was supposed to have an angular diameter of 2.4” and my scope has a theoretical resolving power of 1.2”. But given the performance of SAR (might we say that Some Assembly Required might be a euphemism for Sorry Assed Refractor – it really isn’t quite that bad) I was probably pushing the envelope. CalSky listed the event as follows: Separation=0.030° Position Angle=59.8° Transit duration=3.61s Angular diameter=2.4" cylindrical, 18.0m x 4.5m Satellite at Azimuth=196.7° SSW, Altitude= 18.7°, Distance=1609.0 km (in shadow) Satellite apparently moves to clock-face direction 11:28 o'clock Angular Velocity=8.3'/s Centerline, Closest Point: Longitude= 73°59'10" W, Latitude=+40°45'53", Distance=0.88 km, Azimuth=291.8° WNW, Path direction= 21.8° NNE, ground speed=11.985 km/s, width=96.9 km, max. duration=3.6 s Sun elevation=-22° Elongation from Sun=133° I wasn’t worried about that “(in shadow)” since I interpret it to mean that the satellite was in the Earth’s shadow and would show up as a black mote moving across the illuminated face of the Moon. I think the shadow should have entered the Moon’s disk around Manzinus and entered into the dark side of the moon above Mare Frigoris. When the Moon was behind the clouds the maria looked black. To the 2:00 (mirror reversed) of Tycho, running into the terminator, on the limb, appeared what looked like a wide, crescent-shaped valley. It may have been the craters Scheiner, Blancanus and Klaproth which were appearing foreshortened and merged. Virtual Moon Atlas graphic